MUHWA 40-Hole Vial Rack — 10mL, 25mm Diameter, PP, Stackable
The middle child of the vial rack family. Not as small as the 4mL rack, not as large as the 20mL — it fills the gap for 10mL headspace vials and extraction tubes, which are common enough to need a dedicated rack but not so common that every lab already owns one.
Forty holes, 25mm diameter each, in a 4-row by 10-column grid. The 25mm bore fits the body of a standard 10mL headspace vial (the 22.5x46mm format with a 20mm crimp cap) with just enough clearance for easy insertion and removal — you're not fighting friction, but the vial also isn't swimming in an oversized hole.
Extraction workflows
Ten-milliliter glass tubes with PTFE-lined screw caps see heavy use in liquid-liquid extractions — think EPA methods for water analysis, pesticide residue testing, or alkaloid extractions from plant material. You've got ten samples, each in a 10mL tube with 5mL of hexane and 5mL of aqueous phase. When the phases separate, you need to withdraw the top layer without disturbing the interface. A rack that holds tubes perfectly vertical makes this easier — the interface stays horizontal, and you can see exactly where your pipette tip is relative to it.
How it compares to the 4mL and 20mL racks
Same polypropylene material. Same autoclavable, solvent-resistant properties. Same interlocking stacking design — a 10mL rack stacks on top of another 10mL rack, and it also stacks with the 4mL (16mm) and 20mL (28mm) racks because they share the same footprint and corner post dimensions. If you've got all three sizes in the lab, they nest together in a cabinet as a single tidy column.
Drainage and cleaning
Like its siblings, each well has a drain hole at the bottom. After washing tubes, rack them inverted to drain, or rack them upright and let water drip through. The raised base feet give about 5mm of clearance — enough that water doesn't wick back up from the bench surface. For thorough cleaning, the rack goes into a lab dishwasher (top rack, standard cycle) or an ultrasonic bath with mild detergent. PP doesn't absorb detergent residue the way some softer plastics do, so you won't get surfactant carryover into your next batch of samples.
Specifications
| Positions | 40 (4 rows x 10 columns) |
| Hole diameter | 25mm |
| Compatible vials | 10mL headspace vials, 10mL extraction tubes |
| Material | Polypropylene, autoclavable (121°C) |
| Drainage | Individual well drain holes |
| Stacking | Interlocking with 4mL, 10mL, and 20mL racks |
| Chemical resistance | Hexane, ethyl acetate, DCM (brief), ethanol, methanol, water |
Practical note on labeling
When you're running a batch of extractions, write the sample ID on the vial cap with a fine-point permanent marker — don't rely solely on rack position. Tubes get moved. But the rack provides the secondary confirmation: if you label your notebook "positions 1-10 = samples A-J" and you find tube 3 empty when it shouldn't be, you know something went wrong before it contaminates your data set. Pair the rack with a lab notebook entry and you've got redundancy in your sample tracking.
